Paraspinal epidural
• Facet joint injections
Patients referred for facet injections most often have degenerative disease of the facet joints. However, even if the facet joint appears radiologically normal, facet injections still may be of use, as radiologically occult synovitis can cause facet pain, particularly in younger patients. Postlaminectomy syndrome, or nonradicular pain occurring after laminectomy, is also an acceptable reason to perform facet injections. Patients with lumbar facet pain (so-called facet syndrome) typically present with back, buttock, or hip pain. If the patient has only back pain, this pain may radiate into the buttocks or hips, and the pain is typically worse with extension. A useful test is to ask patients to push the pelvis forward while standing with their hands on their hips because this movement typically reproduces facet-mediated pain. Radiculopathy, leg weakness, and leg numbness are not considered part of the facet syndrome and suggest nerve root compression, although this may be secondarily caused by facet hypertrophy. Occasionally, synovial cysts may be symptomatic. Most often, they cause foraminal or spinal stenosis. These cysts are located adjacent to a facet joint. The injection of steroids into the associated facet joint is effective in resolving synovial cysts in 30-40% of patients, although repeated injections may be necessary. Cervical facet pain is not characterized as easily as lumbar facet pain, and it can occur with a variety of symptoms, depending on the level and the individual patient. Headaches, neck muscle spasms, and general or focal neck pain can originate from the facet joints. This pain is typically worse when patients extend or turn their neck. In particular, the upper cervical facets can often cause occipital headaches. As in the lumbar spine, radiculopathy or arm weakness and/or numbness should suggest an alternate diagnosis. Nerve root blocks Nerve root blocks with local anesthetic and steroids are used in an attempt to produce long-term relief, primarily in patients with radiculopathy. Multiple causes of radiculopathy have been discovered. Pressure on the nerve may result in an autoimmune response that can elicit pain. Because the venous drainage lies on the outside of the nerve, pressure on the nerve increases the venous pressure, causing a compartment syndrome within the substance of the nerve. This syndrome causes ischemia and pain within the nerve root, and the pain can be referred along the dermatome for the particular root. Phospholipase A has been implicated in radiculopathy as well. This chemical, the production of which is stimulated by extruded nucleus pulposus material, causes inflammation and pain in the adjacent nerve, even when no compression is present. Because steroids have anti-inflammatory actions, injections around the nerve root may reduce the inflammation, decreasing or eliminating the pain. • After diskectomy in patients who have recurrent radiculopathy but no recurrent disk herniation, symptoms are often caused when scar tissue tethers the nerve. Many patients can be treated successfully by using SNRB, although some may require a repeat injection.
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